The invention relates to continuously laying a pipeline on a floor of a body of water using a pipelaying system.
Such pipelaying systems have been build by the applicant for many years now and usually include a pipelaying vessel. The pipelaying vessel has a floating body and arranged on the floating body a permanent vertical reel for storing the pipeline to be laid and a guide, e.g. a guide wheel, for guiding the pipeline to be laid into the body of water towards the floor of the body of water.
When the reel is empty, the pipelaying vessel is usually moved to an onshore assembly and winding site, which comprises an assembly line with at least one working station to join pipe sections end to end. After assembly of the pipeline to be laid, said pipeline is spooled, i.e. winded, onto the permanent reel of the pipelaying vessel. After completely filling the reel, the pipelaying vessel can return to continue the pipelaying process.
A reel for pipeline easily weighs about 700 metric tons and depending on the pipe diameter can store several kilometers of pipeline. For instance using a 25 meter diameter reel, the reel is able to store 7.5 km of pipeline with a pipe diameter of 16 inches or 80 km of pipeline with a pipe diameter of 4 inches. In total, a filled reel, i.e. a reel including pipeline to be laid, may weigh up to 2500 to 3000 metric tons.
A drawback of the current reel pipelaying systems is that pipelaying is a time-consuming and inefficient process.